Metal working apparatus



April 1959 R. s. FRIEDMAN 2,881,297

METAL WORKI-NG APPARATUS Filed July 29, 1957 INVEN TOR. N 1 ROBERT 6.FIPIt'D YAIV BY )E/CHEY, W4 7 0651? 701v. Ms? an? RE/Msro/v.

ATTOR EYS United States Patent 2,881,297 METAL WORKING APPARATUS RobertG. Friedman, Tiflin, Ohio, assignor to The NatinaalliMachinery Company,Tiflin, Ohio, a corporation 0 0 Application July 29, 1957, Serial No.674,694 3 Claims. (Cl. 21910.47)

This invention relates to apparatus for making metal articles and moreparticularly to a heating apparatus combined with a header for makingbolts, or the like, from round rod stock.

Numerous attempts have been made to utilize hot rod stock in headersinasmuch as the stock being softened by heating greatly lowers theworking pressures relative to the working pressures where the stock isworked cold as in cold headers. Such prior art efforts have includedmeans for heating the stock between the stock coil and the feed rollsand attempts to use such arrangements have required the provision ofwire brushes, or the like, to remove the scale from the hot rod stockprior to its being cut off and worked in the dies of the header. Hot rodstock is diflicult to feed because of the tendency of the hot stock todeform under the pressure of the feed rolls. It will also be understoodby those skilled in the art that the heating of the stock and theexposure of the hot stock to atmosphere results in the formation of hardoxides and scale particles which adversely affect the life of the diesin which such material is worked.

According to the present invention, relatively cold rod stock from astock coil enters the feed rolls and such stock is heated between thefeed rolls and the shear, and the heating apparatus provided in thislocation includes means to prevent the formation of scale and means toprevent the hot rod stock from heating up the bed frame of the machinein that location where the stock enters the machine.

It is among the objects of the present invention to provide a heatingapparatus for a header which is mounted between the feed rolls and thecutoff for the header and wherein the stock nearest the feed rolls isheated by induction heating and the stock adjacent the shear ismaintained at an elevated temperature by resistance heating and whereinthe hot stock between the feed rolls and the shear is maintained in aninert or non-oxidizing atmosphere so as to prevent the formation ofscale.

It is a further object of this invention to provide an apparatusaccording to the preceding object wherein the resistance heating deviceis surrounded by cooling coils to limit the transmission of heat fromthe resistance heating element to the bed frame of the header.

Further objects and advantages will appear from the followingdescription and the appended drawings, wherein:

Fig. l is a perspective view with parts in section showing the feedingapparatus as mounted in a header; and

Fig. 2 is a sectional elevation showing the arrangement for gauging thehot stock to be cut and the shear.

The invention is illustrated in the environment of a header in Fig. 1 ofthe type having a bed frame 14 and feed rolls 18 to advance the stockinto the header. The machine is preferably of the type disclosed inUnited States Patent No. 2,139,936 to William L. Clouse and assigned tothe National Machinery Company of Tiifin, Ohio. Such machines include aheader slide provided with tools and bed frame dies wherein the blankcut from rod stock is shaped. Such machines also include means to drivethe feed rolls in timed relation to the header slide movement so thatthe stock 18b is intermittently advanced against a stock gauge 56 andmeans operating in timed relation to the header slide to mave the shearindicated at 12 so that on each cycle of the machine a new blank is cutoff and a finished blank is discharged from the machine.

According to the present invention, the bed frame 14 is provided with anenlarged tubular bore 16 in which the heating apparatus is mounted. Thisbore is concentrically aligned with the rod stock 18b being advancedinto the machine by the feed rolls 18 against the stock gauge 56. Thearrangement is such that about half of the heating device is within thebore 16 and the other half projects outside of the bed frame toward thefeed rolls.

Aligned ceramic tubes 20 and 26 surround the rod stock 18b between thefeed rolls and the block 48 which is fixed in the bed frame. Theoutermost ceramic tube 20 is provided with an induction heating coil 28which terminates in leads 28a and 28b leading to a high frequencyelectric power source. The ceramic tube 26 is disposed mainly within thebed frame bore and projects slightly beyond the face of the bed frame 14and in said projected area is provided with a plurality of openings 30.The projecting end of the tube 26 is surrounded in the area of saidopenings by an annular chamber 24 having an inlet pipe 32 to admit aninert gas in the direction indicated by arrow 32a. The hollow chamber 24is also secured to the flange 22 of the outermost ceramic tube 20.

The diameter of the ceramic tubes 20 and 26 is greater than the outerdiameter of the rod stock 18b and since the inner end of the tube 26 issubstantially closed at the shear, the inert gas admitted at 32a maymove outwardly around the rod stock and exit as indicated by arrow 32b.In this way all of the rod stock within the tubes 26 and 20 ismaintained under a non-oxidizing atmosphere and the formation of scaleis prevented. A resistance heater 34 is provided by resistance heatingwires wrapped about a tube 26 within the bed frame. The wires of heater34 terminate at connectors 36 and 38 adapted to be connected to a sourceof electric current. The resistance heater 34 is surrounded by athermoinsulating tubular structure 40 and a metal sleeve 42 in turnencloses the thermo-insulating material 40. A cooling coil unit 46having an inlet and outlet 46a and 46b, respectively, is applied to theexterior of the metal tube 42 and the entire assembly, including thecooling coil, is mounted in the bore 16 by means of flanges such as 44carried by the tube 42 being anchored to the bed frame.

The shear mechanism 12 includes a movable shear block 52 having ahardened metal shearing quill 54 therein. The shear block 12reciprocates as indicated by the arrow 12a transversely of the plate 48mounted on the bed frame. The fixed plate 48 is provided with a tubularmember 50 which extends Within the ceramic tube 26. It will be noted byreference to Fig. 2 that the tubular bushing member 50 snugly fits theouter diameter of the rod stock 18b and also the inner diameter of thetube 26 and thus the inert gas is retained in the ceramic tubularstructure except for exit at the open end of tube 20. When the shearblock 52 moves to the left as viewed in Fig. 1, it is moved so that theshearing quill 54 is brought into alignment with an ejector 62 mountedin the bed frame bore 58. It will be understood that the header includesmeans (not shown) to move the ejector 62 in timed relation to the shearblock 52 so that a cut blank may be ejected from the shear block 52 intotransfer fingers so that the cut blank may be trans ferred to the firstdie working station.

In the operation of this invention a suitable inert gas is admitted intoenclosure 24 through inlet pipe 32 and is therefrom admitted to tubes 20and 26 and into insert 50. Suitable electrical connections arepreferably made to each of induction coil 28 and resistance heater 34whereby the chamber within tube 26 is raised to a predeterminedtemperature. Thereafter stock material is fed through rollers 18 from asupply reel or other source into tube 20 wherein the stock is quicklyheated by induction coil 28. The outer periphery of the stock materialin initially heated to greater temperatures than the inner core and asthestock is moved axially along tube 20 into tube 26, the soaking orheat flow from the periphery to the core in the stock piece effects auniform temperature throughout the piece. The stock piece is advancedfrom within. tube 20 to the region within tube 26 wherein the heatgenerated by resistance heater 34 retains the stock piece at atemperature substantially equivalent to the temperature assumed therebyafter completion of its soaking. Purely as an example, in the operationof this invention under one set of conditions, having regard for thesize and type of stock material, the operation to be performed thereonand the like, the stock piece is advanced through tube 20 at a ratewhereby the temperature of the outer portion of the piece is raised to apoint within the range of 1400 F. to 1600 F. and the temperature withintube 26 is maintained from 1000 to 1200". Subsequent to inductionheating of the stock piece a heat distribution takes place thereinwhereby the same assumes an even temperature throughout, which is withinthe temperature range of tube 26. Accordingly, the primary function oftube 26 is to merely maintain the temperature of the stock piece as thesame advances to shear 12 from within tube 20.

.As the stock piece advances along tube 26 it enters the hollowofinsert50 in plate 48 and the hollow of insert 54 in shear block 52 whenthe same is in alignment with insert 50. The advancement of the stockpiece within these inserts is limited by stock gauge 56.

Suitable mechanism as in said Clouse patent is operative to impart areciprocating sliding movement to shear block 52 whereby the stock piecemay be severed at the junction-of inserts 50 and 54. Subsequent toejection of the severed piece for working thereof, the shear block 52 isreturnable to receive another length of the stock piece that wasconditioned in the manner described. Suitable mechanism as in theaforesaid Clouse patent may be provided for advancing rollers 18 uponthe return of shear block 52 in automatic timed relationship wherebyconditioning, severing and advancing of the stock takes place in acontinuous, orderly sequence to produce a multiplicity of pieces forworking.

It is noted that in all stages of heating and conditioning of the stockmaterial the same is in an atmosphere of an inert gas and that the stockpiece by virtue of the proximity of the conditioner to the shear is notsubjected or exposed to:cold atmosphere or cold parts in its advancementfrom the'conditioner to the shear. Advantages resulting from thesefeatures are the freedom from scale forming influences on the stockpiece during heating and during-transfer to the shear and the obviatingof need for heating the stock material to higher temperatures to allowfor cooling of the same in its transfer from heater to shear. Scaleformation being minimized the damaging effect to the'working dies issimilarly minimized.

Having thus described thisinventionin such full, clear, concise andexact terms as to enable any person skilled in the art to which itpertains to make and use the same, and having set forth the best modecontemplated of carrying out this invention, I state that the subjectmatter which I regard as" being'mydiii/ention isparticularly pointed outand distinctIyF-Tclaimed in what is claimed, it being understood thatequivalents or modifications of, or substitutions for, parts of theabove specifically described embodiment of the invention may be madewithout departing from the scope of the invention as set forth in whatis claimed.

I claim:

1. In combination, a header having a bed frame and a pair ofco-operating feed rolls mounted on the bed frame for intermittentlyadvancing stock into the header, a shear and a stock gauge, means toheat the stock between the feed rolls and the shear comprising a pair ofabutting co-axially aligned tubes carried by the bed frame andproportioned to loosely surround the stock between the feed rolls andthe shear, induction heating means on that tube adjacent the feed rollsand resistance heating means on the tube adjacent the shear, and meansto introduce an inert gas into the tubes at the junction of the tubes,said resistance heating means being provided with a cylindricalthermo-insulating unit to confine the heat to the tube adjacent theshear and said thermo-insulating unit having a cooling coil surroundingthe same to prevent the heating of the bed frame.

2. In combination with a metal working apparatus having a bed frame andshear means for shearing stock material entering the bed frame, a firstenclosure for receiving apiece of stock, an induction heater surroundingsaid enclosure for heating the same to a predetermined temperature, asecond enclosure in alignment with the first enclosure, said secondenclosure being disposed within said bed frame, an electrical heatingelement coiled about said second enclosure for heating the space thereinto a temperature below said predetermined temperature, insulating meansand means for circulating a coolant around said second enclosure toprevent transfer of heat from said second enclosure to said bed frame,and a pair of rolls for-advancing stock material progressively throughsaid first and second chambers to said shear means whereby actuation ofthe shear produces cut lengths of scale-free stock for working in saidapparatus.

3. Metal conditioning and shearing apparatus comprising a bed frame, atubular opening in the bed frame, a shear mounted for reciprocationtransversely of said opening, said shear having an opening thereinadapted to be aligned with the tubular opening of the bed frame at oneend of the shear reciprocation, a stock material conditioning devicehaving a first enclosure with an induction heating coil surrounding theenclosure, a second enclosure disposed in the said tubular opening inthe bed frame and having a heating coil therein, means including aninsulator and cooling coil for preventing transfer of heat from saidsecond enclosure to said bed frame, means for delivering an inert gas tosaid enclosures whereby stock material being advanced therethrough isWithin an inert atmosphere during the heating of the stock, and meansfor advancing said stock material through said enclosure to said shearwhereby scalingand cooling of said stock is prevented prior to theshearing of the stock.

References Cited in the file of this patent UNITED STATES PATENTS2,139,936 Clouse Dec. 13, 1938 2,275,763 Howard et al. Mar. 10, 19422,338,330 Huebner- Ian. 4, 1944 2,441,500 Miess May 11, '1948 2,504,440'Miess Apr. 18, 1950 2,555,450 Lee June 5, 1951

